Supporters of health care reform stand in front of the Supreme Court in Washington, Wednesday, March 28, 2012, on the final day of arguments regarding the health care law enacted in 2010 and signed into law by President Barack Obama. (AP Photo/Charles Dharapak)

While states were previously only required to offer Medicaid to low-income people in specific categories, the 2010 law would require states to cover all individuals under age 65 with incomes up to 133 percent of the poverty level, as noted by NBC News.

The expansion of the Medicaid program for low-income Americans is an important feature in extending health insurance to an additional 30 million people.

It seemed apparent the justices commonly considered the court's most liberal will vote to uphold the Medicaid expansion, which would take in 15 million people with the federal government paying almost all the costs.

Justices Sonia Sotomayor, Elena Kagan, Ruth Bader Ginsburg and Stephen Breyer questioned the argument posed by the 26 states challenging the law that the expansion of the program is unconstitutionally coercive.

"Why is a big gift from the federal government a matter of coercion?" Kagan asked.

Justice Anthony M. Kennedy, often seen as the swing vote on the court, wondered whether Medicaid created accountability problems because the federal government set the rules but the states must operate it, reports The New York Times.

CNN reports the long-standing fight over the power the national government has over states might soon see new heights: The Supreme Court's decision could strengthen or limit congressional authority.

If the Medicaid expansion or any other section of the health care law is deemed unconstitutional, the Obama administration currently has no contingency plans, White House staff said this afternoon.

White House spokesman Josh
Earnest said that after three days of oral arguments before the court,
the White House remained focused on enacting all the provisions of the
law. "We remain confident that they're going to find the entire thing
constitutional," he said.

Earnest faced a barrage of questions in the face
of skepticism voiced by conservative justices that indicated that the
law's key provision requiring most Americans to obtain health insurance
was in jeopardy, The Associated Press reported.

"Anybody who believes you can try to predict the
outcome of the Supreme Court based solely on the questions of the
justices is not a very good student of the Supreme Court," he said.